Decoding method and apparatus for block-based digitally encoded picture

Abstract

A decoding method for block-based digital encoded picture is disclosed. The method including the steps of reconstructing a zeroth reference picture list and a first reference picture list for a current picture based on a predetermined digital picture coding protocol; establishing a lookup table which includes a parameter field for storing a distance scalar, the distance scalar being derived from the time sequence characteristic values of the current picture, the co-located picture and a predetermined reference picture; determining a derived motion vector of a direct mode bi-predictive block according to the distance scalar and a predetermined motion vector of a co-located block with respect to the predetermined reference picture. An apparatus for implementing the method is also disclosed.

1 . A decoding method for block-based digitally encoded pictures, comprising:
 reconstructing a zeroth reference picture list and a first reference picture list for a current picture according to a digital picture encoding protocol, the current picture comprising a direct mode bi-predictive block, and the zeroth reference picture list and the first reference picture list storing access information for decoded pictures during decoding the current picture;   obtaining access information for the co-located picture of the current picture through the first reference picture list, the co-located picture comprising a co-located block of the direct mode bi-predictive block, and the co-located block having the same coordinate as that of the direct mode bi-predictive block;   obtaining a predetermined index through the access information for the co-located picture, and acquiring the access information of a predetermined reference picture of the co-located block through the predetermined index;   determining a reference index by searching the zeroth reference picture list, the reference index being an index of an entry storing the access information of the predetermined reference picture in the zeroth reference picture list;   saving the reference index into an index field of an entry indexed by the predetermined index in a first data structure; and   determining a derived motion vector of the direct mode bi-predictive block according to a time sequence characteristic value of the current picture, the time sequence characteristic value of the co-located picture, the time sequence characteristic value of the predetermined reference picture and a predetermined motion vector of the co-located block with respect to the predetermined reference picture.   
   
   
       2 . The decoding method as claimed in  claim 1 , wherein the first data structure is a look up table which further includes a parameter field for storing a distance scalar, the distance scalar being derived from the time sequence characteristic value of the current picture, the time sequence characteristic value of the co-located picture and the time sequence characteristic value of the predetermined reference picture. 
   
   
       3 . The decoding method as claimed in  claim 2 , wherein the derived motion vector is calculated by multiplying the predetermined motion vector by the distance scalar. 
   
   
       4 . The decoding method as claimed in  claim 1 , wherein the access information of the predetermined reference picture is acquired from an entry indexed by the predetermined index in a second data structure. 
   
   
       5 . The decoding method as claimed in  claim 4 , wherein the second data structure is a second reference picture list for storing the access information of decoded pictures during decoding the co-located picture. 
   
   
       6 . The decoding method as claimed in  claim 1 , wherein the access information comprises an index associated with a decoded picture storage area. 
   
   
       7 . The decoding method as claimed in  claim 1 , wherein the direct mode bi-predictive block is an 8×8 pixel block. 
   
   
       8 . The decoding method as claimed in  claim 1 , wherein the time sequence characteristic value is Picture Order Count (POC). 
   
   
       9 . The decoding method as claimed in  claim 1 , wherein the digital picture encoding protocol is H.264. 
   
   
       10 . A decoding method for block-based digitally encoded pictures, comprising:
 reconstructing a zeroth reference picture list and a first reference picture list for a current picture according to a digital picture encoding protocol, the current picture comprising a direct mode bi-predictive block, and the zeroth reference picture list and the first reference picture list storing access information for decoded pictures during decoding the current picture;   establishing a look up table which comprises an entry containing a parameter field for storing a distance scalar, the distance scalar being derived from a time sequence characteristic value of the current picture, the time sequence characteristic value of a co-located picture and the time sequence characteristic value of a predetermined reference picture of a co-located block;   determining a derived motion vector of the direct mode bi-predictive block according to the parameter field and a predetermined motion vector of the co-located block with respect to the predetermined reference picture,   wherein the access information of the co-located picture is in the first reference picture list, and the co-located block is a block in the co-located picture and has the same coordinate with the direct mode bi-predictive block.   
   
   
       11 . The decoding method as claimed in  claim 10 , wherein the entry of the lookup table further comprises an index field for storing a reference index associated with the zeroth reference picture list, the reference index being an index of an entry storing the access information of the predetermined reference picture in the zeroth reference picture list. 
   
   
       12 . The decoding method as claimed in  claim 10 , wherein the derived motion vector is calculated by multiplying the predetermined motion vector by the distance scalar. 
   
   
       13 . The decoding method as claimed in  claim 10 , wherein the access information of the predetermined reference picture is acquired from an entry indexed by a predetermined index in a predetermined data structure. 
   
   
       14 . The decoding method for block-based digital encoded picture as claimed in  claim 13 , wherein the predetermined data structure is a second reference picture list for storing the access information of decoded pictures during decoding the co-located picture. 
   
   
       15 . The decoding method for block-based digital encoded picture as claimed in  claim 10 , wherein the access information comprises an index associated with a decoded picture storage area. 
   
   
       16 . A decoding apparatus for block-based digitally encoded pictures, comprising:
 a reference picture list reconstruction unit, configured for reconstructing a zeroth reference picture list and a first reference picture list for a current picture according to a digital picture encoding protocol, the current picture comprising a direct mode bi-predictive block, and the zeroth reference picture list and the first reference picture list storing access information for decoded pictures during decoding the current picture;   a lookup table construction unit, configured for establishing a lookup table which comprises an entry containing an index field for storing a reference index associated with the zeroth reference picture list; and   a motion vector deriving unit, configured for acquiring an access information of a predetermined reference picture of a co-located block, and determining a derived motion vector of the direct mode bi-predictive block according to a time sequence characteristic value of the co-located picture containing the co-located block, the time sequence characteristic value of the predetermined reference picture and a predetermined motion vector of the co-located block with respect to the predetermined reference picture,   wherein the access information of the co-located picture is in the first reference picture list, and the co-located block has the same coordinate with the direct mode bi-predictive block in the co-located picture.   
   
   
       17 . The decoding apparatus as claimed in  claim 16 , wherein the entry of the look up table further comprises a parameter field for storing a distance scalar derived from the time sequence characteristic value of the current picture, the time sequence characteristic value of the co-located picture and the time sequence characteristic value of the predetermined reference picture. 
   
   
       18 . The decoding apparatus as claimed in  claim 17 , wherein the derived motion vector equals the predetermined motion vector multiplied by the distance scalar. 
   
   
       19 . The decoding apparatus as claimed in  claim 16 , wherein the access information of the predetermined reference picture is acquired from an entry indexed by a predetermined index in a predetermined data structure. 
   
   
       20 . The decoding apparatus as claimed in  claim 19 , wherein the predetermined data structure is a second reference picture list for storing the access information of decoded pictures during decoding the co-located picture.